Harley J. BrownUniversity of Nottingham, Garreth MartinUniversity of Nottingham, Frazer R. PearceUniversity of Nottingham, Nina A. HatchUniversity of Nottingham, Yannick M. BahéEcole Polytechnique Fédérale de Lausanne, Yohan DuboisInstitut d'Astrophysique de Paris
The diffuse stellar component of galaxy clusters made up of intergalactic stars is termed the intracluster light (ICL). Though there is a developing understanding of the mechanisms by which the ICL is formed, no strong consensus has yet been reached on which objects the stars of the ICL are primarily sourced from. We investigate the assembly of the ICL starting approximately $10$ Gyr before $z=0$ in 11 galaxy clusters (halo masses between $sim1times 10^{14}$ M$_{odot}$ and $sim7times 10^{14}$ M$_{odot}$ at $zapprox0$) in the Horizon-AGN simulation. By tracking the stars of galaxies that fall into these clusters past cluster infall, we are able to link almost all of the $zapprox0$ ICL back to progenitor objects. Satellite stripping, mergers, and pre-processing are all found to make significant contributions to the ICL, but any contribution from in-situ star-formation directly into the ICL appears negligible. Even after compensating for resolution effects, we find that approximately $90$ per cent of the stacked ICL of the 11 clusters that is not pre-processed should come from galaxies infalling with stellar masses above $10^{9}$ M$_{odot}$, with roughly half coming from infalling galaxies with stellar masses within half a dex of $10^{11}$ M$_{odot}$. The fact that the ICL appears largely sourced from such massive objects suggests that the ICL assembly of any individual cluster may be principally stochastic.
{"title":"Assembly of the Intracluster Light in the Horizon-AGN Simulation","authors":"Harley J. BrownUniversity of Nottingham, Garreth MartinUniversity of Nottingham, Frazer R. PearceUniversity of Nottingham, Nina A. HatchUniversity of Nottingham, Yannick M. BahéEcole Polytechnique Fédérale de Lausanne, Yohan DuboisInstitut d'Astrophysique de Paris","doi":"arxiv-2409.10607","DOIUrl":"https://doi.org/arxiv-2409.10607","url":null,"abstract":"The diffuse stellar component of galaxy clusters made up of intergalactic\u0000stars is termed the intracluster light (ICL). Though there is a developing\u0000understanding of the mechanisms by which the ICL is formed, no strong consensus\u0000has yet been reached on which objects the stars of the ICL are primarily\u0000sourced from. We investigate the assembly of the ICL starting approximately\u0000$10$ Gyr before $z=0$ in 11 galaxy clusters (halo masses between $sim1times\u000010^{14}$ M$_{odot}$ and $sim7times 10^{14}$ M$_{odot}$ at $zapprox0$) in\u0000the Horizon-AGN simulation. By tracking the stars of galaxies that fall into\u0000these clusters past cluster infall, we are able to link almost all of the\u0000$zapprox0$ ICL back to progenitor objects. Satellite stripping, mergers, and\u0000pre-processing are all found to make significant contributions to the ICL, but\u0000any contribution from in-situ star-formation directly into the ICL appears\u0000negligible. Even after compensating for resolution effects, we find that\u0000approximately $90$ per cent of the stacked ICL of the 11 clusters that is not\u0000pre-processed should come from galaxies infalling with stellar masses above\u0000$10^{9}$ M$_{odot}$, with roughly half coming from infalling galaxies with\u0000stellar masses within half a dex of $10^{11}$ M$_{odot}$. The fact that the\u0000ICL appears largely sourced from such massive objects suggests that the ICL\u0000assembly of any individual cluster may be principally stochastic.","PeriodicalId":501187,"journal":{"name":"arXiv - PHYS - Astrophysics of Galaxies","volume":"52 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. PaganiLERMA, Arnaud BellocheMPIFR, Bérengère PariseMPIFR
Context. IRAS 16293E is a rare case of a prestellar core being subjected to the effects of at least one outflow.Aims. We want to disentangle the actual structure of the core from the outflow impact and evaluate the evolutionary stage of the core. Methods. Prestellar cores being cold and depleted, the best tracers of their central regions are the two isotopologues of trihydrogren cation which are observable from the ground, ortho-H$_2$D and para-D$_2$H . We used the Atacama Pathfinder EXperiment (APEX) telescope to map the para-D$_2$H$^+$ emission in IRAS 16293E and collected James Clerk Maxwell Telescope (JCMT) archival data of ortho-H$_2$D$^+$ . We compare their emission to that of other tracers, including dust emission, and analyse their abundance with the help of a 1D radiative transfer tool. The ratio of the abundances of ortho-H$_2$D$^+$ and para-D$_2$H$^+$ can be used to estimate the stage of the chemical evolution of the core.Results. We have obtained the first complete map of para-D$_2$H$^+$ emission in a prestellar core. We compare it to a map of ortho-H$_2$D$^+$ and show their partial anti-correlation. This reveals a strongly evolved core with a para-D$_2$H$^+$/ortho-H$_2$D$^+$ abundance ratio towards the centre for which we obtain a conservative lower limit from 3.9 (at 12 K) up to 8.3 (at 8 K) while the high extinction of the core is indicative of a central temperature below 10 K. This ratio is higher than predicted by the known chemical models found in the literature. Para-D$_2$H$^+$ (and indirectly ortho-H$_2$D$^+$) is the only species that reveals the true centre of this core, while the emission of other molecular tracers and dust are biased by the temperature structure that results from the impact of the outflow.Conclusions. This study invites to reconsider the analysis of previous observations of this source and possibly questions the validity of the deuteration chemical models or of the reaction and inelastic collisional rate coefficients of the H$^{+3}$ isotopologue family. This could impact the deuteration clock predictions for all sources.
背景。IRAS 16293E 是一个罕见的前恒星内核受到至少一次外流影响的案例。我们希望将内核的实际结构与流出物的影响区分开来，并评估内核的演化阶段。方法。前恒星核心是寒冷和贫化的，其中心区域的最佳示踪剂是从地面观测到的三氢化的两个同位素，即正H$_2$D和对位D$_2$H。我们利用阿塔卡马探路者实验（APEX）望远镜绘制了 IRAS 16293E 中的对位-D$_2$H$^+$ 辐射图，并收集了詹姆斯-克拉克-麦克斯韦望远镜（JCMT）的正交-H$_2$D$^+$ 档案数据。我们将它们的发射与包括尘埃发射在内的其他示踪剂的发射进行了比较，并借助一维辐射传递工具分析了它们的丰度。北-H$_2$D$^+$和对位-D$_2$H$^+$的丰度比可用来估计地核化学演化的阶段。我们获得了第一张完整的前恒星内核对位-D$_2$H$^+$发射图。我们将其与北H$_2$D$^+$的地图进行了比较，并显示了它们的部分反相关性。这揭示了强烈演化的内核，其对位-D$_2$H$^+$/北-H$_2$D$^+$丰度比向中心倾斜，我们得到了一个保守的下限，从 3.9（12 K 时）到 8.3（8 K 时），而内核的高消光表明中心温度低于 10 K。对位-D$_2$H$^+$（以及间接对位-H$_2$D$^+$）是揭示该核心真正中心的唯一物种，而其他分子示踪剂和尘埃的发射则受到了外流撞击产生的温度结构的影响。这项研究促使我们重新考虑以前对该星源的观测分析，并可能质疑氘化化学模型或 H$^{+3}$ 异同位素家族的反应和非弹性碰撞速率系数的有效性。这可能会影响对所有来源的氘化钟预测。
{"title":"First map of D$_2$H$^+$ emission revealing the true centre of a prestellar core: further insights into deuterium chemistry","authors":"L. PaganiLERMA, Arnaud BellocheMPIFR, Bérengère PariseMPIFR","doi":"arxiv-2409.10093","DOIUrl":"https://doi.org/arxiv-2409.10093","url":null,"abstract":"Context. IRAS 16293E is a rare case of a prestellar core being subjected to\u0000the effects of at least one outflow.Aims. We want to disentangle the actual\u0000structure of the core from the outflow impact and evaluate the evolutionary\u0000stage of the core. Methods. Prestellar cores being cold and depleted, the best\u0000tracers of their central regions are the two isotopologues of trihydrogren\u0000cation which are observable from the ground, ortho-H$_2$D and para-D$_2$H . We\u0000used the Atacama Pathfinder EXperiment (APEX) telescope to map the\u0000para-D$_2$H$^+$ emission in IRAS 16293E and collected James Clerk Maxwell\u0000Telescope (JCMT) archival data of ortho-H$_2$D$^+$ . We compare their emission\u0000to that of other tracers, including dust emission, and analyse their abundance\u0000with the help of a 1D radiative transfer tool. The ratio of the abundances of\u0000ortho-H$_2$D$^+$ and para-D$_2$H$^+$ can be used to estimate the stage of the\u0000chemical evolution of the core.Results. We have obtained the first complete map\u0000of para-D$_2$H$^+$ emission in a prestellar core. We compare it to a map of\u0000ortho-H$_2$D$^+$ and show their partial anti-correlation. This reveals a\u0000strongly evolved core with a para-D$_2$H$^+$/ortho-H$_2$D$^+$ abundance ratio\u0000towards the centre for which we obtain a conservative lower limit from 3.9 (at\u000012 K) up to 8.3 (at 8 K) while the high extinction of the core is indicative of\u0000a central temperature below 10 K. This ratio is higher than predicted by the\u0000known chemical models found in the literature. Para-D$_2$H$^+$ (and indirectly\u0000ortho-H$_2$D$^+$) is the only species that reveals the true centre of this\u0000core, while the emission of other molecular tracers and dust are biased by the\u0000temperature structure that results from the impact of the outflow.Conclusions.\u0000This study invites to reconsider the analysis of previous observations of this\u0000source and possibly questions the validity of the deuteration chemical models\u0000or of the reaction and inelastic collisional rate coefficients of the H$^{+3}$\u0000isotopologue family. This could impact the deuteration clock predictions for\u0000all sources.","PeriodicalId":501187,"journal":{"name":"arXiv - PHYS - Astrophysics of Galaxies","volume":"34 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We present the discovery of a luminous X-ray AGN in the dwarf galaxy merger RGG 66. The black hole is predicted to have a mass of $M_{rm BH} sim 10^{5.4} M_odot$ and to be radiating close to its Eddington limit ($L_{rm bol}/L_{rm Edd} sim 0.75$). The AGN in RGG 66 is notable both for its presence in a late-stage dwarf-dwarf merger and for its luminosity of $L_{rm 2-10~keV} = 10^{42.2}$ erg s$^{-1}$, which is among the most powerful AGNs known in nearby dwarf galaxies. The X-ray spectrum has a best-fit photon index of $Gamma = 2.4$ and an intrinsic absorption of $N_H sim 10^{21}$ cm$^{-2}$. These results come from a follow-up {it Chandra X-ray Observatory} study of four irregular/disturbed dwarf galaxies with evidence for hosting AGNs based on optical spectroscopy. The remaining three dwarf galaxies do not have detectable X-ray sources with upper limits of $L_{rm 2-10~ keV} lesssim 10^{40}$ erg s$^{-1}$. Taken at face value, our results on RGG 66 suggest that mergers may trigger the most luminous of AGNs in the dwarf galaxy regime, just as they are suspected to do in more massive galaxy mergers.
{"title":"A Luminous X-ray AGN in the Dwarf-Dwarf Galaxy Merger RGG 66","authors":"Seth Kimbrell, Amy Reines","doi":"arxiv-2409.10630","DOIUrl":"https://doi.org/arxiv-2409.10630","url":null,"abstract":"We present the discovery of a luminous X-ray AGN in the dwarf galaxy merger\u0000RGG 66. The black hole is predicted to have a mass of $M_{rm BH} sim 10^{5.4}\u0000M_odot$ and to be radiating close to its Eddington limit ($L_{rm bol}/L_{rm\u0000Edd} sim 0.75$). The AGN in RGG 66 is notable both for its presence in a\u0000late-stage dwarf-dwarf merger and for its luminosity of $L_{rm 2-10~keV} =\u000010^{42.2}$ erg s$^{-1}$, which is among the most powerful AGNs known in nearby\u0000dwarf galaxies. The X-ray spectrum has a best-fit photon index of $Gamma =\u00002.4$ and an intrinsic absorption of $N_H sim 10^{21}$ cm$^{-2}$. These results\u0000come from a follow-up {it Chandra X-ray Observatory} study of four\u0000irregular/disturbed dwarf galaxies with evidence for hosting AGNs based on\u0000optical spectroscopy. The remaining three dwarf galaxies do not have detectable X-ray sources with\u0000upper limits of $L_{rm 2-10~ keV} lesssim 10^{40}$ erg s$^{-1}$. Taken at\u0000face value, our results on RGG 66 suggest that mergers may trigger the most\u0000luminous of AGNs in the dwarf galaxy regime, just as they are suspected to do\u0000in more massive galaxy mergers.","PeriodicalId":501187,"journal":{"name":"arXiv - PHYS - Astrophysics of Galaxies","volume":"196 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Recent observations by the James Webb Telescope (JWST) have unveiled numerous galaxy candidates between $z sim 9 - 16.5$, hinting at an over-abundance of the bright-end of the UV Luminosity Function (UV LF) $z gtrsim 11$. Possible solutions require extremely bursty star formation, these systems being dust-free, an evolving initial mass function or even cosmic variance. In this work, we develop an analytic formalism to study dust enrichment and its impact on the UV luminosity of both main-sequence early galaxies and extremely bursty star formers. Our dust model, including the key processes of dust production in type II Supernovae, dust destruction, ejection, growth and sputtering, is calibrated against the latest datasets from the Atacama Large Millimeter Array (ALMA) at $z sim 4-7$. The model has only 3 free parameters: (i) the star formation efficiency; (ii) the dust growth timescale; and (iii) the dust distribution radius. Our key results are: (i) explaining the observed UV LF requires an average star formation efficiency that increases with redshift as $f_*(z) = 10^{0.13z-3.5}$ at $z sim 5-13$ with a number of observations hinting at objects lying a factor 10 above this main-sequence. (ii) The dust enrichment of early systems is driven by dust production in SNII ejecta; growth and sputtering are the second and third most crucial processes, impacting the dust mass by 60% and 40% respectively at $z sim 7$. (iii) In our model, galaxies at $z gtrsim 9$ can still host significant amounts of dust reaching average dust-to-stellar mass ratios of 0.19% (0.14%) at $z sim 9$ ($z sim 11$). Dust attenuation decreases with redshift due to dust being increasingly more dispersed within the halo. (iv) the galaxies observed by ALMA at $z sim 7$ comprise a biased sample that is not representative of the average population that makes up the UV LF.
{"title":"A phenomenological model for bright galaxies in the high-redshift Universe","authors":"Georgios Panagiotis Nikopoulos, Pratika Dayal","doi":"arxiv-2409.10613","DOIUrl":"https://doi.org/arxiv-2409.10613","url":null,"abstract":"Recent observations by the James Webb Telescope (JWST) have unveiled numerous\u0000galaxy candidates between $z sim 9 - 16.5$, hinting at an over-abundance of\u0000the bright-end of the UV Luminosity Function (UV LF) $z gtrsim 11$. Possible\u0000solutions require extremely bursty star formation, these systems being\u0000dust-free, an evolving initial mass function or even cosmic variance. In this\u0000work, we develop an analytic formalism to study dust enrichment and its impact\u0000on the UV luminosity of both main-sequence early galaxies and extremely bursty\u0000star formers. Our dust model, including the key processes of dust production in\u0000type II Supernovae, dust destruction, ejection, growth and sputtering, is\u0000calibrated against the latest datasets from the Atacama Large Millimeter Array\u0000(ALMA) at $z sim 4-7$. The model has only 3 free parameters: (i) the star\u0000formation efficiency; (ii) the dust growth timescale; and (iii) the dust\u0000distribution radius. Our key results are: (i) explaining the observed UV LF\u0000requires an average star formation efficiency that increases with redshift as\u0000$f_*(z) = 10^{0.13z-3.5}$ at $z sim 5-13$ with a number of observations\u0000hinting at objects lying a factor 10 above this main-sequence. (ii) The dust\u0000enrichment of early systems is driven by dust production in SNII ejecta; growth\u0000and sputtering are the second and third most crucial processes, impacting the\u0000dust mass by 60% and 40% respectively at $z sim 7$. (iii) In our model,\u0000galaxies at $z gtrsim 9$ can still host significant amounts of dust reaching\u0000average dust-to-stellar mass ratios of 0.19% (0.14%) at $z sim 9$ ($z sim\u000011$). Dust attenuation decreases with redshift due to dust being increasingly\u0000more dispersed within the halo. (iv) the galaxies observed by ALMA at $z sim\u00007$ comprise a biased sample that is not representative of the average\u0000population that makes up the UV LF.","PeriodicalId":501187,"journal":{"name":"arXiv - PHYS - Astrophysics of Galaxies","volume":"49 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Serena Perrotta, Alison L. Coil, David S. N. Rupke, Wenmeng Ning, Brendan Duong, Aleksandar M. Diamond-Stanic, Drummond B. Fielding, James E. Geach, Ryan C. Hickox, John Moustakas, Gregory H. Rudnick, Paul H. Sell, Cameren N. Swiggum, Christy A. Tremonti
High-velocity outflows are ubiquitous in compact, massive (M$_* sim$ 10$^{11}$ M$_{odot}$), z $sim$ 0.5 galaxies with extreme star formation surface densities ($Sigma_{SFR} sim$ 2000 M$_{odot}$ yr$^{-1}$ kpc$^{-2}$). We have previously detected and characterized these outflows using MgII absorption lines. To probe their full extent, we present Keck/KCWI integral field spectroscopy of the [OII] and MgII emission nebulae surrounding all of the 12 galaxies in this study. We find that [OII] is more effective than MgII in tracing low surface brightness, extended emission in these galaxies. The [OII] nebulae are spatially extended beyond the stars, with radial extent R$_{90}$ between 10 and 40 kpc. The nebulae exhibit non-gravitational motions, indicating galactic outflows with maximum blueshifted velocities ranging from -335 to -1920 km s$^{-1}$. The outflow kinematics correlate with the bursty star formation histories of these galaxies. Galaxies with the most recent bursts of star formation (within the last $<$ 3 Myr) exhibit the highest central velocity dispersions ($sigma >$ 400 km s$^{-1}$), while the oldest bursts have the lowest-velocity outflows. Many galaxies exhibit both high-velocity cores and more extended, slower-moving gas indicative of multiple outflow episodes. The slower, larger outflows occurred earlier and have decelerated as they propagate into the CGM and mix on timescales $>$ 50 Myr.
{"title":"The Outflowing [OII] Nebulae of Compact Starburst Galaxies at z $sim$ 0.5","authors":"Serena Perrotta, Alison L. Coil, David S. N. Rupke, Wenmeng Ning, Brendan Duong, Aleksandar M. Diamond-Stanic, Drummond B. Fielding, James E. Geach, Ryan C. Hickox, John Moustakas, Gregory H. Rudnick, Paul H. Sell, Cameren N. Swiggum, Christy A. Tremonti","doi":"arxiv-2409.10013","DOIUrl":"https://doi.org/arxiv-2409.10013","url":null,"abstract":"High-velocity outflows are ubiquitous in compact, massive (M$_* sim$\u000010$^{11}$ M$_{odot}$), z $sim$ 0.5 galaxies with extreme star formation\u0000surface densities ($Sigma_{SFR} sim$ 2000 M$_{odot}$ yr$^{-1}$ kpc$^{-2}$).\u0000We have previously detected and characterized these outflows using MgII\u0000absorption lines. To probe their full extent, we present Keck/KCWI integral\u0000field spectroscopy of the [OII] and MgII emission nebulae surrounding all of\u0000the 12 galaxies in this study. We find that [OII] is more effective than MgII\u0000in tracing low surface brightness, extended emission in these galaxies. The\u0000[OII] nebulae are spatially extended beyond the stars, with radial extent\u0000R$_{90}$ between 10 and 40 kpc. The nebulae exhibit non-gravitational motions,\u0000indicating galactic outflows with maximum blueshifted velocities ranging from\u0000-335 to -1920 km s$^{-1}$. The outflow kinematics correlate with the bursty\u0000star formation histories of these galaxies. Galaxies with the most recent\u0000bursts of star formation (within the last $<$ 3 Myr) exhibit the highest\u0000central velocity dispersions ($sigma >$ 400 km s$^{-1}$), while the oldest\u0000bursts have the lowest-velocity outflows. Many galaxies exhibit both\u0000high-velocity cores and more extended, slower-moving gas indicative of multiple\u0000outflow episodes. The slower, larger outflows occurred earlier and have\u0000decelerated as they propagate into the CGM and mix on timescales $>$ 50 Myr.","PeriodicalId":501187,"journal":{"name":"arXiv - PHYS - Astrophysics of Galaxies","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142269538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mathias Lipka, Jens Thomas, Roberto Saglia, Ralf Bender, Maximilian Fabricius, Gary J. Hill, Matthias Kluge, Martin Landriau, Ximena Mazzalay, Eva Noyola, Taniya Parikh, Jan Snigula
We analyse the stellar structure of a sample of dwarf ellipticals (dE) inhabiting various environments within the Virgo cluster. Integral-field observations with a high spectral resolution allow us to robustly determine their low velocity dispersions ($sim25$ km s$^{-1}$) and higher-order kinematic moments out to the half-light radius. We find the dEs exhibit a diversity in ages with the younger dEs being less enhanced than the older, suggesting a complex star formation history for those dEs that recently entered Virgo while others have been quenched shortly after reionization. Orbit-superposition modeling allowed us to recover viewing angles, stellar mass-to-light ratios (with gradients), as well as the intrinsic orbit structure. We find that the angular momentum of the dEs is strongly suppressed compared to ordinary early-type galaxies and correlates with the environment. Flattened dEs are so because of a suppressed kinetic energy perpendicular to their equatorial plane. Combining population and dynamical modeling results, we find an age-dependent stellar initial mass function (IMF) or, alternatively, evidence for a more extended star formation history for those galaxies that have had higher initial mass and/or inhabited lower density environments. dEs appear to have a spatially homogeneous stellar structure but the state they were `frozen' in as they stopped forming stars varies dramatically according to their initial conditions.
我们分析了居住在室女座星团内各种环境中的矮椭圆（dE）样本的恒星结构。高光谱分辨率的积分场观测使我们能够稳健地确定它们的低速弥散（$sim25$ km s$^{-1}$）和半光半径范围内的高阶运动力矩。我们发现dEs在年龄上呈现出多样性，年轻的dEs比年老的dEs增强得更少，这表明那些最近才进入Virgo的dEs有着复杂的恒星形成史，而其他的dEs则在再电离后不久就被熄灭了。我们发现，与普通的早期型星系相比，dEs的角动量受到了强烈的抑制，并且与环境相关。结合种群和动力学建模结果，我们发现了一个与年龄相关的恒星初始质量函数（IMF），或者，对于那些初始质量较高和/或所处环境密度较低的星系，有证据表明它们的恒星形成历史更长。
{"title":"The VIRUS-dE Survey I: Stars in dwarf elliptical galaxies - 3D dynamics and radially resolved stellar initial mass functions","authors":"Mathias Lipka, Jens Thomas, Roberto Saglia, Ralf Bender, Maximilian Fabricius, Gary J. Hill, Matthias Kluge, Martin Landriau, Ximena Mazzalay, Eva Noyola, Taniya Parikh, Jan Snigula","doi":"arxiv-2409.10518","DOIUrl":"https://doi.org/arxiv-2409.10518","url":null,"abstract":"We analyse the stellar structure of a sample of dwarf ellipticals (dE)\u0000inhabiting various environments within the Virgo cluster. Integral-field\u0000observations with a high spectral resolution allow us to robustly determine\u0000their low velocity dispersions ($sim25$ km s$^{-1}$) and higher-order\u0000kinematic moments out to the half-light radius. We find the dEs exhibit a\u0000diversity in ages with the younger dEs being less enhanced than the older,\u0000suggesting a complex star formation history for those dEs that recently entered\u0000Virgo while others have been quenched shortly after reionization.\u0000Orbit-superposition modeling allowed us to recover viewing angles, stellar\u0000mass-to-light ratios (with gradients), as well as the intrinsic orbit\u0000structure. We find that the angular momentum of the dEs is strongly suppressed\u0000compared to ordinary early-type galaxies and correlates with the environment.\u0000Flattened dEs are so because of a suppressed kinetic energy perpendicular to\u0000their equatorial plane. Combining population and dynamical modeling results, we\u0000find an age-dependent stellar initial mass function (IMF) or, alternatively,\u0000evidence for a more extended star formation history for those galaxies that\u0000have had higher initial mass and/or inhabited lower density environments. dEs\u0000appear to have a spatially homogeneous stellar structure but the state they\u0000were `frozen' in as they stopped forming stars varies dramatically according to\u0000their initial conditions.","PeriodicalId":501187,"journal":{"name":"arXiv - PHYS - Astrophysics of Galaxies","volume":"98 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Carter Rhea, Julie Hlavacek-Larrondo, Alexandre Adam, Ralph Kraft, Akos Bogdan, Laurence Perreault-Levasseur, Marine Prunier
Recent advances in machine learning algorithms have unlocked new insights in observational astronomy by allowing astronomers to probe new frontiers. In this article, we present a methodology to disentangle the intrinsic X-ray spectrum of galaxy clusters from the instrumental response function. Employing state-of-the-art modeling software and data mining techniques of the Chandra data archive, we construct a set of 100,000 mock Chandra spectra. We train a recurrent inference machine (RIM) to take in the instrumental response and mock observation and output the intrinsic X-ray spectrum. The RIM can recover the mock intrinsic spectrum below the 1-$sigma$ error threshold; moreover, the RIM reconstruction of the mock observations are indistinguishable from the observations themselves. To further test the algorithm, we deconvolve extracted spectra from the central regions of the galaxy group NGC 1550, known to have a rich X-ray spectrum, and the massive galaxy clusters Abell 1795. Despite the RIM reconstructions consistently remaining below the 1-$sigma$ noise level, the recovered intrinsic spectra did not align with modeled expectations. This discrepancy is likely attributable to the RIM's method of implicitly encoding prior information within the neural network. This approach holds promise for unlocking new possibilities in accurate spectral reconstructions and advancing our understanding of complex X-ray cosmic phenomena.
机器学习算法的最新进展使天文学家能够探索新的前沿领域，从而开启了观测天文学的新视野。在这篇文章中，我们介绍了一种将星系团的固有X射线光谱与仪器响应函数分离开来的方法。利用最先进的建模软件和钱德拉数据档案的数据挖掘技术，我们构建了一组 10 万个模拟钱德拉光谱。我们训练电流推理机（RIM），以接收仪器响应和模拟观测，并输出本征 X 射线光谱。推理机能够恢复低于 1-$sigma$ 误差阈值的模拟本征光谱；此外，推理机重建的模拟观测结果与观测结果本身没有区别。为了进一步测试该算法，我们对从星系团 NGC 1550（已知有丰富的 X 射线光谱）和大质量星系团 Abell 1795 的中心区域提取的光谱进行了解卷积。尽管RIM重构始终保持在1-$sigma$噪声水平以下，但恢复的本征光谱与模型预期并不一致。这种差异很可能归因于 RIM 在神经网络中隐含编码先前信息的方法。这种方法有望解锁精确光谱重建的新可能性，并推进我们对复杂 X 射线宇宙现象的理解。
{"title":"Deconvolving X-ray Galaxy Cluster Spectra Using a Recurrent Inference Machine","authors":"Carter Rhea, Julie Hlavacek-Larrondo, Alexandre Adam, Ralph Kraft, Akos Bogdan, Laurence Perreault-Levasseur, Marine Prunier","doi":"arxiv-2409.10711","DOIUrl":"https://doi.org/arxiv-2409.10711","url":null,"abstract":"Recent advances in machine learning algorithms have unlocked new insights in\u0000observational astronomy by allowing astronomers to probe new frontiers. In this\u0000article, we present a methodology to disentangle the intrinsic X-ray spectrum\u0000of galaxy clusters from the instrumental response function. Employing\u0000state-of-the-art modeling software and data mining techniques of the Chandra\u0000data archive, we construct a set of 100,000 mock Chandra spectra. We train a\u0000recurrent inference machine (RIM) to take in the instrumental response and mock\u0000observation and output the intrinsic X-ray spectrum. The RIM can recover the\u0000mock intrinsic spectrum below the 1-$sigma$ error threshold; moreover, the RIM\u0000reconstruction of the mock observations are indistinguishable from the\u0000observations themselves. To further test the algorithm, we deconvolve extracted\u0000spectra from the central regions of the galaxy group NGC 1550, known to have a\u0000rich X-ray spectrum, and the massive galaxy clusters Abell 1795. Despite the\u0000RIM reconstructions consistently remaining below the 1-$sigma$ noise level,\u0000the recovered intrinsic spectra did not align with modeled expectations. This\u0000discrepancy is likely attributable to the RIM's method of implicitly encoding\u0000prior information within the neural network. This approach holds promise for\u0000unlocking new possibilities in accurate spectral reconstructions and advancing\u0000our understanding of complex X-ray cosmic phenomena.","PeriodicalId":501187,"journal":{"name":"arXiv - PHYS - Astrophysics of Galaxies","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Koshy George, B. M. Poggianti, A. Omizzolo, B. Vulcani, P. Côté, J. Postma, R. Smith, Y. L. Jaffe, M. Gullieuszik, A. Moretti, A. Subramaniam, P. Sreekumar, S. K. Ghosh, S. N. Tandon, J. B. Hutchings
The assembly of galaxy clusters is understood to be a hierarchical process with a continuous accretion of galaxies over time, which increases the cluster size and mass. Late-type galaxies that fall into clusters can undergo ram-pressure stripping, forming extended gas tails within which star formation can happen. The number, location, and tail orientations of such galaxies provide clues about the galaxy infall process, the assembly of the cluster over time, and the consequences of infall for galaxy evolution. Here, we utilise the $sim$ 0.5 degree diameter circular field of the Ultraviolet Imaging Telescope to image six galaxy clusters at z < 0.06 that are known to contain jellyfish galaxies. We searched for stripping candidates in the ultraviolet images of these clusters, which revealed 54 candidates showing signs of unilateral extra-planar emission, due to ram-pressure stripping. Seven candidates had already been identified as likely stripping based on optical B-band imaging. We identified 47 new candidates through UV imaging. Spectroscopic redshift information is available for 39 of these candidate galaxies, of which 19 are associated with six clusters. The galaxies with spectroscopic redshifts that are not part of the clusters appear to be within structures at different redshifts identified as additional peaks in the redshift distribution of galaxies, indicating that they might be ram-pressure stripped or disturbed galaxies in other structures along the line of sight. We examine the orbital history of these galaxies based on their location in the position-velocity phase-space diagram and explore a possible connection to the orientation of the tail direction among cluster member candidates. The tails of confirmed cluster member galaxies are found to be oriented away from the cluster centre.
{"title":"Candidate ram-pressure stripped galaxies in six low-redshift clusters revealed from ultraviolet imaging","authors":"Koshy George, B. M. Poggianti, A. Omizzolo, B. Vulcani, P. Côté, J. Postma, R. Smith, Y. L. Jaffe, M. Gullieuszik, A. Moretti, A. Subramaniam, P. Sreekumar, S. K. Ghosh, S. N. Tandon, J. B. Hutchings","doi":"arxiv-2409.10586","DOIUrl":"https://doi.org/arxiv-2409.10586","url":null,"abstract":"The assembly of galaxy clusters is understood to be a hierarchical process\u0000with a continuous accretion of galaxies over time, which increases the cluster\u0000size and mass. Late-type galaxies that fall into clusters can undergo\u0000ram-pressure stripping, forming extended gas tails within which star formation\u0000can happen. The number, location, and tail orientations of such galaxies\u0000provide clues about the galaxy infall process, the assembly of the cluster over\u0000time, and the consequences of infall for galaxy evolution. Here, we utilise the\u0000$sim$ 0.5 degree diameter circular field of the Ultraviolet Imaging Telescope\u0000to image six galaxy clusters at z < 0.06 that are known to contain jellyfish\u0000galaxies. We searched for stripping candidates in the ultraviolet images of\u0000these clusters, which revealed 54 candidates showing signs of unilateral\u0000extra-planar emission, due to ram-pressure stripping. Seven candidates had\u0000already been identified as likely stripping based on optical B-band imaging. We\u0000identified 47 new candidates through UV imaging. Spectroscopic redshift\u0000information is available for 39 of these candidate galaxies, of which 19 are\u0000associated with six clusters. The galaxies with spectroscopic redshifts that\u0000are not part of the clusters appear to be within structures at different\u0000redshifts identified as additional peaks in the redshift distribution of\u0000galaxies, indicating that they might be ram-pressure stripped or disturbed\u0000galaxies in other structures along the line of sight. We examine the orbital\u0000history of these galaxies based on their location in the position-velocity\u0000phase-space diagram and explore a possible connection to the orientation of the\u0000tail direction among cluster member candidates. The tails of confirmed cluster\u0000member galaxies are found to be oriented away from the cluster centre.","PeriodicalId":501187,"journal":{"name":"arXiv - PHYS - Astrophysics of Galaxies","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
George P. Prodan, Mario Pasquato, Giuliano Iorio, Alessandro Ballone, Stefano Torniamenti, Ugo Niccolò Di Carlo, Michela Mapelli
Context. Computational astronomy has reached the stage where running a gravitational N-body simulation of a stellar system, such as a Milky Way star cluster, is computationally feasible, but a major limiting factor that remains is the ability to set up physically realistic initial conditions. Aims. We aim to obtain realistic initial conditions for N-body simulations by taking advantage of machine learning, with emphasis on reproducing small-scale interstellar distance distributions. Methods. The computational bottleneck for obtaining such distance distributions is the hydrodynamics of star formation, which ultimately determine the features of the stars, including positions, velocities, and masses. To mitigate this issue, we introduce a new method for sampling physically realistic initial conditions from a limited set of simulations using Gaussian processes. Results. We evaluated the resulting sets of initial conditions based on whether they meet tests for physical realism. We find that direct sampling based on the learned distribution of the star features fails to reproduce binary systems. Consequently, we show that physics-informed sampling algorithms solve this issue, as they are capable of generating realisations closer to reality.
背景。计算天文学已经发展到可以对恒星系统（如银河系星团）进行引力 N 体模拟计算的阶段，但仍然存在的一个主要限制因素是设置物理上真实的初始条件的能力。我们的目标我们的目标是利用机器学习的优势，为 N-体模拟获取现实的初始条件，重点是再现小尺度的星际距离分布。方法。获得这种距离分布的计算瓶颈是恒星形成的流体力学，它最终决定了恒星的特征，包括位置、速度和质量。为了缓解这一问题，我们引入了一种新方法，利用高斯过程从有限的模拟集合中采样物理上真实的初始条件。结果。我们根据所得到的初始条件集是否符合物理现实性检验标准对其进行了评估。我们发现，基于恒星特征分布的直接采样无法再现双星系统。因此，我们证明了物理信息采样算法能够解决这个问题，因为它们能够生成更接近现实的模拟。
{"title":"A machine learning framework to generate star cluster realisations","authors":"George P. Prodan, Mario Pasquato, Giuliano Iorio, Alessandro Ballone, Stefano Torniamenti, Ugo Niccolò Di Carlo, Michela Mapelli","doi":"arxiv-2409.10627","DOIUrl":"https://doi.org/arxiv-2409.10627","url":null,"abstract":"Context. Computational astronomy has reached the stage where running a\u0000gravitational N-body simulation of a stellar system, such as a Milky Way star\u0000cluster, is computationally feasible, but a major limiting factor that remains\u0000is the ability to set up physically realistic initial conditions. Aims. We aim\u0000to obtain realistic initial conditions for N-body simulations by taking\u0000advantage of machine learning, with emphasis on reproducing small-scale\u0000interstellar distance distributions. Methods. The computational bottleneck for\u0000obtaining such distance distributions is the hydrodynamics of star formation,\u0000which ultimately determine the features of the stars, including positions,\u0000velocities, and masses. To mitigate this issue, we introduce a new method for\u0000sampling physically realistic initial conditions from a limited set of\u0000simulations using Gaussian processes. Results. We evaluated the resulting sets\u0000of initial conditions based on whether they meet tests for physical realism. We\u0000find that direct sampling based on the learned distribution of the star\u0000features fails to reproduce binary systems. Consequently, we show that\u0000physics-informed sampling algorithms solve this issue, as they are capable of\u0000generating realisations closer to reality.","PeriodicalId":501187,"journal":{"name":"arXiv - PHYS - Astrophysics of Galaxies","volume":"119 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nora SalemHaverford College, Karen MastersHaverford College, David StarkSTScI, Anubhav SharmaHaverford College
HI-rich galaxies typically have high star-formation rates (SFR), but there exist interesting HI-rich and low star-forming (low-SF) galaxies. Previous work on a sample of these galaxies identified from HI-MaNGA (HI follow-up to the MaNGA survey) using an infrared indicator of specific-SFR (sSFR; namely W2-W3~<2) could find no single physical process to explain their unusual behaviour. The method by which galaxies are identified as low sSFR may be important in this conclusion. In this Research Note, we explore how an HI-rich, low sSFR sample of HI-MaNGA galaxies differs using H alpha, single stellar population, and ultraviolet estimators of SFR. We find that samples are statistically similar to each other so long as W2-W3~<2 is interpreted as corresponding to sSFR<10^{-11.15} yr^{-1}.
富含 HI 的星系通常具有较高的恒星形成率（SFR），但也存在一些有趣的富含 HI 但恒星形成率较低（low-SF）的星系。以前的研究利用红外比SFR（即W2-W3~<2）指标，对从HI-MaNGA（MaNGA巡天的HI后续）中确定的这些星系样本进行了研究，但没有发现任何单一的物理过程可以解释它们的异常行为。在得出这一结论时，确定星系为低比SFR的方法可能很重要。在这份研究报告中，我们使用Hα、单恒星群和紫外线估计SFR的方法，探讨了富含HI、低sSFR的HI-MaNGA星系样本的不同之处。我们发现，只要将W2-W3~<2解释为对应于sSFR<10^{-11.15} yr^{-1}，样本之间在统计上是相似的。
{"title":"Finding Passive Galaxies in HI-MaNGA: The Impact of Star-Formation Rate Indicator","authors":"Nora SalemHaverford College, Karen MastersHaverford College, David StarkSTScI, Anubhav SharmaHaverford College","doi":"arxiv-2409.09574","DOIUrl":"https://doi.org/arxiv-2409.09574","url":null,"abstract":"HI-rich galaxies typically have high star-formation rates (SFR), but there\u0000exist interesting HI-rich and low star-forming (low-SF) galaxies. Previous work\u0000on a sample of these galaxies identified from HI-MaNGA (HI follow-up to the\u0000MaNGA survey) using an infrared indicator of specific-SFR (sSFR; namely\u0000W2-W3~<2) could find no single physical process to explain their unusual\u0000behaviour. The method by which galaxies are identified as low sSFR may be\u0000important in this conclusion. In this Research Note, we explore how an HI-rich,\u0000low sSFR sample of HI-MaNGA galaxies differs using H alpha, single stellar\u0000population, and ultraviolet estimators of SFR. We find that samples are\u0000statistically similar to each other so long as W2-W3~<2 is interpreted as\u0000corresponding to sSFR<10^{-11.15} yr^{-1}.","PeriodicalId":501187,"journal":{"name":"arXiv - PHYS - Astrophysics of Galaxies","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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